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1.
Josef T. Boronski Dr. Laurence R. Doyle Dr. John A. Seed Dr. Ashley J. Wooles Prof. Dr. Stephen T. Liddle 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(1):301-305
Despite there being numerous examples of f-element compounds supported by cyclopentadienyl, arene, cycloheptatrienyl, and cyclooctatetraenyl ligands (C5–8), cyclobutadienyl (C4) complexes remain exceedingly rare. Here, we report that reaction of [Li2{C4(SiMe3)4}(THF)2] ( 1 ) with [U(BH4)3(THF)2] ( 2 ) gives the pianostool complex [U{C4(SiMe3)4}(BH4)3][Li(THF)4] ( 3 ), where use of a borohydride and preformed C4-unit circumvents difficulties in product isolation and closing a C4-ring at uranium. Complex 3 is an unprecedented example of an f-element half-sandwich cyclobutadienyl complex, and it is only the second example of an actinide-cyclobutadienyl complex, the other being an inverse-sandwich. The U−C distances are short (av. 2.513 Å), reflecting the formal 2− charge of the C4-unit, and the SiMe3 groups are displaced from the C4-plane, which we propose maximises U−C4 orbital overlap. DFT calculations identify two quasi-degenerate U−C4 π-bonds utilising the ψ2 and ψ3 molecular orbitals of the C4-unit, but the potential δ-bond using the ψ4 orbital is vacant. 相似文献
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Triamidoamine–Uranium(IV)‐Stabilized Terminal Parent Phosphide and Phosphinidene Complexes 下载免费PDF全文
Dr. Benedict M. Gardner Dr. Gábor Balázs Prof. Dr. Manfred Scheer Dr. Floriana Tuna Prof. Eric J. L. McInnes Dr. Jonathan McMaster Dr. William Lewis Prof. Alexander J. Blake Prof. Stephen T. Liddle 《Angewandte Chemie (International ed. in English)》2014,53(17):4484-4488
Reaction of [U(TrenTIPS)(THF)][BPh4] ( 1 ; TrenTIPS=N{CH2CH2NSi(iPr)3}3) with NaPH2 afforded the novel f‐block terminal parent phosphide complex [U(TrenTIPS)(PH2)] ( 2 ; U–P=2.883(2) Å). Treatment of 2 with one equivalent of KCH2C6H5 and two equivalents of benzo‐15‐crown‐5 ether (B15C5) afforded the unprecedented metal‐stabilized terminal parent phosphinidene complex [U(TrenTIPS)(PH)][K(B15C5)2] ( 4 ; U?P=2.613(2) Å). DFT calculations reveal a polarized‐covalent U?P bond with a Mayer bond order of 1.92. 相似文献
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Mono‐ and Bimetallic Alkynyl Metallocenes and Half‐Sandwich Complexes: A Simple and Versatile Synthetic Approach 下载免费PDF全文
Dr. María C. de la Torre Prof. Dr. José Luis García Ruano Dr. José Alemán Dr. Luis Casarrubios Dr. Miguel A. Sierra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15645-15649
A general process for the synthesis of alkynyl mono and dimetallic metallocenes and half‐sandwich complexes has been developed. This approach uses the addition of lithium derivatives of sandwich or half‐sandwich complexes to arylsulfonylacetylenes. The reaction occurs in two steps (lithiation and anti‐Michael addition to alkynylsulfone followed by elimination of the ArSO2 moiety) to form the corresponding mono‐ or bimetallic alkynes in clearly higher yields, simpler experimental procedures, and more environmentally benign conditions than those of the so far reported for the synthesis of this type of products. The electrochemical properties of the newly obtained complexes have also been studied. 相似文献
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Guy M. Jones Prof. Polly L. Arnold Dr. Jason B. Love 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(31):10287-10294
Simple and versatile routes to the functionalization of uranyl‐derived UV–oxo groups are presented. The oxo‐lithiated, binuclear uranium(V)–oxo complexes [{(py)3LiOUO}2(L)] and [{(py)3LiOUO}(OUOSiMe3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide “ate” complex [Li(py)2][(OUO)(N”)3] (N”=N(SiMe3)2) with the polypyrrolic macrocycle H4L or the mononuclear uranyl (VI) Pacman complex [UO2(py)(H2L)], respectively. These oxo‐metalated complexes display distinct U? O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo–stannylated complexes [{(R3Sn)OUO}2(L)] (R=nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium–oxo‐group exchange occurred in reactions with [TiCl(OiPr)3] to form U‐O? C bonds [{(py)3LiOUO}(OUOiPr)(L)] and [(iPrOUO)2(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo‐functionalised by Group 14 elements. 相似文献
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Dr. Erli Lu Josef T. Boronski Dr. Matthew Gregson Dr. Ashley J. Wooles Prof. Stephen T. Liddle 《Angewandte Chemie (International ed. in English)》2018,57(19):5506-5511
Unprecedented silyl‐phosphino‐carbene complexes of uranium(IV) are presented, where before all covalent actinide–carbon double bonds were stabilised by phosphorus(V) substituents or restricted to matrix isolation experiments. Conversion of [U(BIPMTMS)(Cl)(μ‐Cl)2Li(THF)2] ( 1 , BIPMTMS=C(PPh2NSiMe3)2) into [U(BIPMTMS)(Cl){CH(Ph)(SiMe3)}] ( 2 ), and addition of [Li{CH(SiMe3)(PPh2)}(THF)]/Me2NCH2CH2NMe2 (TMEDA) gave [U{C(SiMe3)(PPh2)}(BIPMTMS)(μ‐Cl)Li(TMEDA)(μ‐TMEDA)0.5]2 ( 3 ) by α‐hydrogen abstraction. Addition of 2,2,2‐cryptand or two equivalents of 4‐N,N‐dimethylaminopyridine (DMAP) to 3 gave [U{C(SiMe3)(PPh2)}(BIPMTMS)(Cl)][Li(2,2,2‐cryptand)] ( 4 ) or [U{C(SiMe3)(PPh2)}(BIPMTMS)(DMAP)2] ( 5 ). The characterisation data for 3 – 5 suggest that whilst there is evidence for 3‐centre P?C?U π‐bonding character, the U=C double bond component is dominant in each case. These U=C bonds are the closest to a true uranium alkylidene yet outside of matrix isolation experiments. 相似文献
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Dr. Maria A. Antunes Joana T. Coutinho Dr. Isabel C. Santos Dr. Joaquim Marçalo Prof. Manuel Almeida José J. Baldoví Dr. Laura C. J. Pereira Dr. Alejandro Gaita‐Ariño Prof. Eugenio Coronado 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17817-17826
A tetravalent uranium compound with a radical azobenzene ligand, namely, [{(SiMe2NPh)3‐tacn}UIV(η2‐N2Ph2.)] ( 2 ), was obtained by one‐electron reduction of azobenzene by the trivalent uranium compound [UIII{(SiMe2NPh)3‐tacn}] ( 1 ). Compound 2 was characterized by single‐crystal X‐ray diffraction and 1H NMR, IR, and UV/Vis/NIR spectroscopy. The magnetic properties of 2 and precursor 1 were studied by static magnetization and ac susceptibility measurements, which for the former revealed single‐molecule magnet behaviour for the first time in a mononuclear UIV compound, whereas trivalent uranium compound 1 does not exhibit slow relaxation of the magnetization at low temperatures. A first approximation to the magnetic behaviour of these compounds was attempted by combining an effective electrostatic model with a phenomenological approach using the full single‐ion Hamiltonian. 相似文献
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Dr. Tyler J. Carter Dr. Richard E. Wilson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15575-15582
The synthesis, X‐ray crystal structure, vibrational and optical spectroscopy for the eight‐coordinate thiocyanate compounds, [Et4N]4[PuIV(NCS)8], [Et4N]4[ThIV(NCS)8], and [Et4N]4[CeIII(NCS)7(H2O)] are reported. Thiocyanate was found to rapidly reduce plutonium to PuIII in acidic solutions (pH<1) in the presence of NCS?. The optical spectrum of [Et4N][SCN] containing PuIII solution was indistinguishable from that of aquated PuIII suggesting that inner‐sphere complexation with [Et4N][SCN] does not occur in water. However, upon concentration, the homoleptic thiocyanate complex [Et4N]4[PuIV(NCS)8] was crystallized when a large excess of [Et4N][NCS] was present. This compound, along with its UIV analogue, maintains inner‐sphere thiocyanate coordination in acetonitrile based on the observation of intense ligand‐to‐metal charge‐transfer bands. Spectroscopic and crystallographic data do not support the interaction of the metal orbitals with the ligand π system, but support an enhanced AnIV–NCS interaction, as the Lewis acidity of the metal ion increases from Th to Pu. 相似文献
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Synthesis of Air‐Stable,Volatile Uranium(IV) and (VI) Compounds and Their Gas‐Phase Conversion To Uranium Oxide Films 下载免费PDF全文
Linus Appel Jennifer Leduc Christopher L. Webster Dr. Joseph W. Ziller Prof. Dr. William J. Evans Prof. Dr. Sanjay Mathur 《Angewandte Chemie (International ed. in English)》2015,54(7):2209-2213
Four air‐stable, volatile uranium heteroarylalkenolates have been synthesized and characterized by three synthetic approaches and their gas phase deposition to uranium oxide films has been examined. 相似文献
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Gev Dovrat Dr. Svetlana Pevzner Dr. Claude Berthon Ana Lerner Dr. Eric Maimon Dr. Radion Vainer Dr. Mark Karpasas Dr. Yeshayahu Ben-Elyiahu Prof. Dr. Philippe Moisy Prof. Dr. Armand Bettelheim Prof. Dr. Israel Zilbermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(32):8264-8267
Two new aqueous UIV complexes were synthesized by the interaction between the tetravalent uranium cation and the (1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetra(methylene phosphonic acid) (DOTP) macrocyclic ligand. Two distinct homonuclear complexes were identified; the first was characterized by X-ray crystallography as a unique “out-of-cage”, [U(DOTPH6)2] complex, in which the UIV cation is octa-coordinated to 4 phosphonic arms from each ligand in a square anti-prism geometry, with a C4 symmetry. The second is the “in-cage” [U(DOTPH4)] complex, in which the tetravalent cation is located between the macrocycle O4 and N4 planes. With the help of UV-Vis absorption, 1H/31P NMR, ATR-IR, and MALDI-TOFMS analytical techniques, the chemical interchange between both species is presented. It is shown that the one-way transition is governed by the formation of a multiple number of soluble oligomeric species consisting of varied stoichiometric ratios of both characterized homonuclear complexes. 相似文献
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Dr. Erli Lu Dr. Ashley J. Wooles Dr. Matthew Gregson Philip J. Cobb Prof. Stephen T. Liddle 《Angewandte Chemie (International ed. in English)》2018,57(22):6587-6591
Reaction of [U{C(SiMe3)(PPh2)}(BIPM)(μ‐Cl)Li(TMEDA)(μ‐TMEDA)0.5]2 (BIPM=C(PPh2NSiMe3)2; TMEDA=Me2NCH2CH2NMe2) with [Rh(μ‐Cl)(COD)]2 (COD=cyclooctadiene) affords the heterotrimetallic UIV?RhI2 complex [U(Cl)2{C(PPh2NSiMe3)(PPh[C6H4]NSiMe3)}{Rh(COD)}{Rh(CH(SiMe3)(PPh2)}]. This complex has a very short uranium–rhodium distance, the shortest uranium–rhodium bond on record and the shortest actinide–transition metal bond in terms of formal shortness ratio. Quantum‐chemical calculations reveal a remarkable Rh UIV net double dative bond interaction, involving RhI 4d ‐ and 4dxy/xz‐type donation into vacant UIV 5f orbitals, resulting in a Wiberg/Nalewajski–Mrozek U?Rh bond order of 1.30/1.44, respectively. Despite being, formally, purely dative, the uranium–rhodium bonding interaction is the most substantial actinide–metal multiple bond yet prepared under conventional experimental conditions, as confirmed by structural, magnetic, and computational analyses. 相似文献
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Tae‐Jin Kim Sung‐Kwan Kim Beom‐Jun Kim Ho‐Jin Son Jong Sok Hahn Minserk Cheong Prof. Mariusz Mitoraj Dr. Monika Srebro Łukasz Piękoś Artur Michalak Prof. Sang Ook Kang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(19):5630-5644
A series of mono‐, bis‐, and tris(phenoxy)–titanium(IV) chlorides of the type [Cp*Ti(2‐R? PhO)nCl3?n] (n=1–3; Cp*=pentamethylcyclopentadienyl) was prepared, in which R=Me, iPr, tBu, and Ph. The formation of each mono‐, bis‐, and tris(2‐alkyl‐/arylphenoxy) series was authenticated by structural studies on representative examples of the phenyl series including [Cp*Ti(2‐Ph? PhO)Cl2] ( 1 PhCl2 ), [Cp*Ti(2‐Ph? PhO)2Cl] ( 2 PhCl ), and [Cp*Ti(2‐Ph? PhO)3] ( 3 Ph ). The metal‐coordination geometry of each compound is best described as pseudotetrahedral with the Cp* ring and the 2‐Ph? PhO and chloride ligands occupying three leg positions in a piano‐stool geometry. The mean Ti? O distances, observed with an increasing number of 2‐Ph? PhO groups, are 1.784(3), 1.802(4), and 1.799(3) Å for 1 PhCl2 , 2 PhCl , and 3 Ph , respectively. All four alkyl/aryl series with Me, iPr, tBu, and Ph substituents were tested for ethylene homopolymerization after activation with Ph3C+[B(C6F5)4]? and modified methyaluminoxane (7% aluminum in isopar E; mMAO‐7) at 140 °C. The phenyl series showed much higher catalytic activity, which ranged from 43.2 and 65.4 kg (mmol of Ti?h)?1, than the Me, iPr, and tBu series (19.2 and 36.6 kg (mmol of Ti?h)?1). Among the phenyl series, the bis(phenoxide) complex of 2 PhCl showed the highest activity of 65.4 kg (mmol of Ti?h)?1. Therefore, the catalyst precursors of the phenyl series were examined by treating them with a variety of alkylating reagents, such as trimethylaluminum (TMA), triisobutylaluminum (TIBA), and methylaluminoxane (MAO). In all cases, 2 PhCl produced the most catalytically active alkylated species, [Cp*Ti(2‐Ph? PhO)MeCl]. This enhancement was further supported by DFT calculations based on the simplified model with TMA. 相似文献
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Triphenylamine‐Appended Half‐Sandwich Iridium(III) Complexes and Their Biological Applications 下载免费PDF全文
Xiangdong He Meng Tian Dr. Xicheng Liu Yanhua Tang Chang Fang Shao Peiwei Gong Jinfeng Liu Shumiao Zhang Lihua Guo Prof. Zhe Liu 《化学:亚洲杂志》2018,13(11):1500-1509
Organometallic half‐sandwich IrIII complexes of the type [(η5‐Cpx)Ir(N^N)Cl]PF6 (Cpx: Cp* or its phenyl Cpxph or biphenyl Cpxbiph derivatives; N^N: triphenylamine (TPA)‐substituted bipyridyl ligand groups) were synthesized and characterized. The complexes showed excellent bovine serum albumin (BSA) and DNA binding properties and were able to oxidize NADH to NAD+ (NAD=nicotinamide adenine dinucleotide) efficiently. The complexes induced apoptosis effectively and led to the emergence of reactive oxygen species (ROS) in cells. All complexes showed potent cytotoxicity with IC50 values ranging from 1.5 to 7.1 μm toward A549 human lung cancer cells after 24 hours of drug exposure, which is up to 14 times more potent than cisplatin under the same conditions. 相似文献
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John A. Seed Helen R. Sharpe Harry J. Futcher Ashley J. Wooles Stephen T. Liddle 《Angewandte Chemie (International ed. in English)》2020,59(37):15870-15874
Treatment of [Ph3EMe][I] with [Na{N(SiMe3)2}] affords the ylides [Ph3E=CH2] (E=As, 1As ; P, 1P ). For 1As this overcomes prior difficulties in the synthesis of this classical arsonium‐ylide that have historically impeded its wider study. The structure of 1As has now been determined, 45 years after it was first convincingly isolated, and compared to 1P , confirming the long‐proposed hypothesis of increasing pyramidalisation of the ylide‐carbon, highlighting the increasing dominance of E+?C? dipolar resonance form (sp3‐C) over the E=C ene π‐bonded form (sp2‐C), as group 15 is descended. The uranium(IV)–cyclometallate complex [U{N(CH2CH2NSiPri3)2(CH2CH2SiPri2CH(Me)CH2)}] reacts with 1As and 1P by α‐proton abstraction to give [U(TrenTIPS)(CHEPh3)] (TrenTIPS=N(CH2CH2NSiPri3)3; E=As, 2As ; P, 2P ), where 2As is an unprecedented structurally characterised arsonium‐carbene complex. The short U?C distances and obtuse U‐C‐E angles suggest significant U=C double bond character. A shorter U?C distance is found for 2As than 2P , consistent with increased uranium‐ and reduced pnictonium‐stabilisation of the carbene as group 15 is descended, which is supported by quantum chemical calculations. 相似文献
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Radmila Faizova Farzaneh Fadaei‐Tirani Rizlan Bernier‐Latmani Marinella Mazzanti 《Angewandte Chemie (International ed. in English)》2020,59(17):6756-6759
Reduction of uranyl(VI) to UV and to UIV is important in uranium environmental migration and remediation processes. The anaerobic reduction of a uranyl UVI complex supported by a picolinate ligand in both organic and aqueous media is presented. The [UVIO2(dpaea)] complex is readily converted into the cis‐boroxide UIV species via diborane‐mediated reductive functionalization in organic media. Remarkably, in aqueous media the uranyl(VI) complex is rapidly converted, by Na2S2O4, a reductant relevant for chemical remediation processes, into the stable uranyl(V) analogue, which is then slowly reduced to yield a water‐insoluble trinuclear UIV oxo‐hydroxo cluster. This report provides the first example of direct conversion of a uranyl(VI) compound into a well‐defined molecular UIV species in aqueous conditions. 相似文献
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Frontispiece: A Rare Tetranuclear Thorium(IV) μ4‐Oxo Cluster and Dinuclear Thorium(IV) Complex Assembled by Carbon–Oxygen Bond Activation of 1,2‐Dimethoxyethane (DME) 下载免费PDF全文
Dr. Nicholas E. Travia Dr. Brian L. Scott Dr. Jaqueline L. Kiplinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51)